From: "Peña, Botp" <botp@...>
Date: 2008-08-23T13:05:55+09:00
Subject: Re: remove_const, Kernel.load, and already instantiated objects

From: Brent Dillingham [mailto:brentdillingham@gmail.com] 
# ...
#      >> puts File.read('foo.rb')
#      class Foo
#        def hello
#          "Hello, world!"
#        end
#      end
#      => nil
#      >> require 'foo'
#      => true

ok. you used require

#      # Reload the file using remove_const and Kernel.load
#      >> Object.send(:remove_const, :Foo)
#      => Foo
#      >> Kernel.load('foo.rb')
#      => true

now you use load.

let us stick to require... ;)

irb(main):001:0> require 'foo.rb'
=> true
irb(main):002:0> f=Foo.new
=> #<Foo:0x2900af4>
irb(main):003:0> f.hello
=> "hello"

ok

irb(main):004:0> require 'foo.rb'
=> false
irb(main):005:0> f.hello
=> "hello"

as expected, no change.
let's see if we can cheat ;)

irb(main):006:0> $LOADED_FEATURES
=> ["e2mmap.rb", "irb/init.rb", "irb/workspace.rb", "irb/context.rb", "irb/extend-command.rb", "irb/output-method.rb", "irb/notifier.rb", "irb/slex.rb", "irb/ruby-token.rb", "irb/ruby-lex.rb", "readline.so", "irb/input-method.rb", "irb/locale.rb", "irb.rb", "irb/ext/history.rb", "irb/ext/save-history.rb", "foo.rb"]

ah

irb(main):007:0> $LOADED_FEATURES.delete "foo.rb"
=> "foo.rb"

irb(main):008:0> require 'foo.rb'
=> true
irb(main):009:0> f.hello
=> "new hello"

is that ok?
... caveat, i'm not sure if that is documented/supported. maybe, verify fr matz or nobu..

kind regards -botp